Double-layer tundish covering agent for ultrathin belt

Abstract

The invention discloses a double-layer tundish covering agent for an ultrathin belt, and relates to the technical field of metallurgy. The upper covering agent and the lower covering agent are hollowgranular products which are subjected to spray granulation. The upper covering agent comprises the following chemical components of, in percentage by weight, 45%-55 wt% of CaO, 18.0-24.0 wt% of SiO2,14.0-18.0 wt% of MgO, less than or equal to 1.9 wt% of Al2O3, 7.5-11.5 wt% of C-solid and the balance inevitable impurities, and the melting point of the upper covering agent is greater than 1450 DEGC. The lower covering agent comprises the following chemical components of, in percentage by weight, 25.0-31.0 wt% of CaO, 27.0-37.0 wt% of SiO2, 13.0-18.0 wt% of MgO, less than or equal to 1.9 wt% ofAl2O3, 13.0-17.0 wt% of (Li2O + Na2O), less than or equal to 0.5 wt% of C-solid and the inevitable balance impurities, and the melting point of the lower covering agent is 1150-1250 DEG C. The product has the advantages that the specific gravity is light, the upper layer is carbon-containing and the lower layer is extremely few in carbon-containing, carbon-increasing is prevented and heat preservation is achieved, the content of Al2O3 in the upper layer and the lower layer is low, the impurities are fully absorbed, the melting point of the upper layer is high, the insulation of the air is isolated, the melting point of the lower layer is low, and rapid melting can be achieved so as to prevent the carbon-containing upper layer from being in contact with the molten steel to increase the carbon.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a double-layer tundish covering agent for an ultra-thin belt and a preparation method thereof. Background technique [0002] Ultra-thin strip production technology is a metallurgical cutting-edge new technology with the most development potential in today's steel industry. It is also a short process, low energy consumption, low investment, low cost and green environmental protection that major steel companies in the world have invested heavily in competing to develop. new technology. [0003] The production process of ultra-thin strip is: molten steel passes through ladle→tundish→transition section→nozzle→casting roll→atmosphere control→pinch roll→hot rolling stand→pull roll→shear→coil. The distance from the tundish to the coiler is only 60 meters, equivalent to one tenth of the slab caster. The steel type for ultra-thin strip steel production is mainly low-carbon steel, the...

AI Technical Summary

Problems solved by technology

This covering agent is divided into three layers, which is too complicated in actual production. The upper and lower layers are not hollow particles, and there is no data to quantify the temperature drop of molten steel.

[0011] Patent CN101486587B "Double-layer tundish covering agent" invented a double-layer tundish covering agent that can prevent crusting on the slag surface. However, the particles are not hollow particles, and the effect of insulating air and heat preservation is not good. In addition, Al 2 o 3 High content is not good for absorbing inclusions

[0012] To sum up, a single acidic covering agent is unfavorable for absorbing floating inclusions and seriously erodes the lining; magnesium covering agents and alkaline covering agents are easy to crust and have poor thermal insulation effect; carbon-free covering agents have poor thermal insulation effect

Especially in the production of ultra-thin strips, the pouring time of each furnace is about 80 minutes, and there is no covering agent on the transition section. The above-mentioned tundish covering agent cannot meet the metallurgical properties required by the ultra-thin strip tundish.

Images